When a listener listens to a music and so on (sound reproduction) by inserting an earphone into the listener's ear, the sound is propagated in order of the earphone, the listener's external auditory canal, and the listener's tympanum. Here, unnecessary resonance characteristic of external auditory canal is acquired by echo from the earphone (reflector), and original necessary resonance characteristic of external auditory canal is lost. In order to avoid this defect, the sound reproduction is amended by suppressing the unnecessary resonance characteristic of external auditory canal and by adding the necessary characteristic. Briefly, a sound reproduction apparatus to near a sound quality in case of insertion of the earphone to a (natural) sound quality in case of non-insertion of the earphone is proposed.
In such sound reproduction apparatus, various earphones are used by the listener to listen to the sound reproduction. Accordingly, even if different earphones are used, it is expected that the sound quality can be improved as mentioned-above.